Mixing apparatus



Dec. 19, 1967. J. M. MITCHELL ETAL 3,353,973

' MIXING APPARATUS I Filed Sept. 26, 1966 2 SheetsSheet 1 ATTORNEY Dec. 19, 1967 M. MITCHELL ETAL $35 ,913

MIXING APPARATUS Filed Sept. 26, 1966 ,2 Sheets-Sheet 2 13b 13b 29 llmlm" I O 1. min '-1 1e so r ATTORNEY United States Patent 3,358,973 MIXING APPARATUS Jack M. Mitchell, 642 N. 17th Ave. 85007, and Clarence D. Hess, 1819 E. Meadowbrook Ave. 85016, both of Phoenix. Ariz.

Filed Sept. 26, 1966, Ser. No. 581,959 6 Claims. (Cl. 259-177) ABSTRACT OF THE DISCLOSURE A portable mixing plant for accurately mixing two or more dry materials with one or more liquid, each introduced at the proper stage of mixing to facilitate process performance.

This invention pertains to material mixing apparatus and is particularly directed to apparatus for mixing asphalt concrete and the like.

It has been clearly proven in many mixing processes that the stage at which various ingredients are introduced are of extreme importance for results to be achieved. As an example, in the preparation and mixing of asphalt slurries, it is essential that all dry ingredients be properly wetted with water before being mixed with asphalt in water emulsions.

The object of this invention is to provide a portable mixing plant capable of accurately mixing two or more dry materials with one or more liquid, each introduced at the proper stage of mixing to facilitate process performance.

Still another objective is to provide a mixing plant that is portable and can be adjusted to introduce the various ingredients at the right time for proper blending and process reaction.

Still another object of this invention is to provide mixing and blending in such a manner as to prevent premature breaking of emulsion or other unstable components being used.

Still another object of this invention is to provide a mixing apparatus than can be used over a wide range of material both in composition and size, thereby adjusting to available materials and supplies.

Still another object of this invention is to provide a variable mixing ratio at various stages, depending upon the angle and speed of paddles provided on horizontal shaft and drum.

One of the objects of this invention is to provide a simple and effective apparatus for mixing asphalt slurry for road surfacing operations.

Still another object of this invention is to provide a portable asphalt mixing plant which is easy to use and dependable in operation.

It is also a further object to provide a mixing device in which a rotating drum revolves in one direction while mixing element within said drum rotates on an eccentric axis within the drum and in the opposite direction to provide a highly desirable mixed end product.

Further features and advantages of this invention will appear from a detailed description of the drawings in which:

FIG. 1 is general perspective view of a mixing apparatus incorporating the features of this invention.

FIG. 2 is an enlarged sectional view on the line 2-2 of FIGS. 1 and 3.

FIG. 3 is an enlarged sectional view on the line 3-3 of FIG. 1.

FIG. 4 is an enlarged perspective view of the cradle of the mixing machine.

FIG. 5 is an enlarged perspective view of the internal mixing element.

As an example of one embodiment of this invention, there is shown a mixing apparatus for asphalt slurry and the like comprising a frame 10 suitably secured to the supply truck 11. A cradle device comprising the transverse supports 12 has the rollers 13 journaled thereon and arranged to rotatably support the mixing drum 14 as best seen in FIG. 3. Top hold-down rollers 13a are journaled on brackets 13b fixed to the frame 10. Radially disposed flanges 15 on the outer cylindrical surface 16 engage between the rollers to restrict axial relative movement of the drum 14 and the frame 10. Projecting radially inwardly from the inside surface 17 of the drum 14 are the angularly pitched mixing paddles 18.

The rear end 19 is closed by a suitable baffle 20 fixed to the frame 10 and includes a chute 21 arranged to receive discharge from a hopper 22a supplied from the truck 11 and a water discharge manifold 21a, FIG. 2, for initially wetting the aggregate as it enters the drum. A mixing element shaft 22 is journaled on suitable bearings 23 supported on the frame 10 rearwardly of the bafiie 20 and has a driven sprocket 24 fixed to the outer end thereof. The shaft passes through a suitable seal 25 into the interior of the drum 14 and has its axis 26 eccentrically located relative to the axis 27 of the drum 14. A series of radially extending angularly pitched paddles 28 are fixed to the shaft 22 and closely rotate between the paddles 18 in the drum 14. The oil supply pipe 31 is connected to a suitable swivel elbow 32 journaled on the shaft 22, the pipe 31 thus communicating with the longitudinal passageway 33 in the shaft. The passageway 33 is closed at 34 and a series of radially disposed dis-charge holes 33a are formed in the shaft 22 in communication with the passageway 33 for discharge of oil into the mixing drum 14.

A drive motor such as the internal combustion engine 29 is mounted on the frame 10 and is connected by suitable transmission drive chain 30 to the driven sprocket 24 on the shaft 22. A sprocket 35 is fixed to the mixing element shaft 22 over which operates the chain 36 and in turn is connected operatively with a sprocket 44 fixed on the input shaft 45 of a suitable reversible gear box 46 having the usual reversing lever 47. The reversible output shaft 48 has a drive sprocket 49 over which operates the mixing drum chain 50 operatively engaging the drum ring sprocket 51 fixed to the outside diameter 16 of the mixing drum 14. The described power transmission from the motor 29 is so arranged that the drum 14 may be rotated in one direction or the other relative to the mixing element shaft 22 which is being rotated at a more rapid rate than the mixing drum 14.

The paddles 18 and 28 are so arranged and pitched that the materials fed into the drum from the hopper 22 and chute 21 are thoroughly and efilciently mixed and fed toward the front end 37 of the drum where the discharged mixed material is controlled by a suitable device such as the vertically slidable door or gate 38 vertically guided on suitable guide tracks 39 fixed to the frame 10, the gate being raised and lowered by the control shaft 40 having the rack and pinion mechanism 41 and the handwheel 42. A discharge slot 43 is formed in the gate which may be moved to a shut position by raising the gate or downwardly to a discharge position of the material as the drum and mixing element are rotating as described.

The paddles 18 and 28 are preferably so arranged and pitched that materials are given preliminary mixing with wetting agent in the first zone, approximately /3 the length of the mixer while moving toward the front end 37 of the drum. In the second zone, approximately the middle /3, additional liquids are added and additional mixing takes place While material is continuously moving toward end 37. The level and intensity of mixing can be controlled by increasing or decreasing the pitch of one .3 or both sets of blades. A sharper drop in level can be achieved by reversing one row of blades to hold a higher level in mixing area than. in discharge area. The remaining portion of drum, approximately /3 has blades pitched for maximum discharge of materials that have been mixed. In the use of rapid set emulsions, it is essential that mixing take place at the last possible moment, and then rapid discharge be accomplished. To further assist in maintaining the level of mixing, the gate opening either vertical moving as shown at 38 or a scissor operated gate may be used to reduce the discharge opening.

While the apparatus herein disclosed and described constitutes a preferred form of the invention, it is also to be understood that the apparatus is capable of mechanical alteration without departing from the spirit of the invention and that such mechanical arrangement and commercial adaptation as fall within the scope of the appendant claims are intended to be included herein.

Having thus fully set forth and described this invention what is claimed and desired to be obtained by United States Letters Patent is:

1. A mixing apparatus comprising in combination:

(A) aframe,

(B) a drum journaled to rotate on said frame,

(C) a plurality of radially inwardly pitched paddles fixed to the inside of said drum,

(D) a mixing element including a shaft projecting into said drum with its axis eccentric to the axis of said drum,

(E) a plurality of radially outwardly pitched paddles fixed on said shaft and revolved by said shaft between said paddles inside of said drum,

(F) power means on said frame for simultaneously rotating said drum and said shaft,

(G) a longitudinal passageway within said shaft,

(H) radially disposed outlets intermediate its ends,

(I) and a source of oil connected to said passageway of said shaft for distributing oil to material being mixed in said drum.

2. In a mixing apparatus as set forth in claim 1 wherein there is:

(J) a supply hopper mounted on said frame,

(K) a chute mounted on said frame having a discharge opening within one end of said drum,

(L) and a water discharge manifold above and at each side of said discharge and of said chute for initially wetting aggregate material as it enters said drum.

3. A portable mixing machine comprising in combination:

(A) a drum rotating around a horizontal axis having closed ends with openings modified to receive predetermined measured amounts of dry aggregates from a truck or other auxiliary components and provision for reliminary wetting with controlled amount of water immediately on entering the mixer,

(B) a mixing element including a hollow shaft projecting into said drum being eccentric to the axis of said drum rotating at a more rapid rate than the drum, said mixing element rotating opposite to the drum to achieve complete mixing,

(C) a spray located at the entrance of the drum to provide immediate wetting of dry aggregate, followed by mixing by angular blades on mixer and drum set to cause material to move to the center section of mixer,

(D) at the center section, asphalt emulsions or other mixing element introduced from hollow shaft through radial openings therein so that the complete mix with all components is given a final mixing in the front 4 or final section, and the final section has paddles set at a greater angle designed to assure rapid discharge through an adjustable gate opening,

(E) and power means to simultaneously rotate said drum and said shaft.

4. A mixing apparatus as set forth in claim 3 but designed for milder blending by rotating both shaft and drum in the same direction, depending on the cascading of material from drum, combined with mixer to provide complete blending of less stable materials wherein the blades in the first two sections of drum and mixer have very slight angle, causing material to move to exit, mostly by static head, and the blades in final section are set to effect rapid discharge.

5. A mixing apparatus comprising in combination:

(A) a drum rotating around a horizontal axis having closed ends with openings modified to receive predetermined measured amounts of dry aggregates from truck or other auxiliary component,

(B) means for wetting said aggregates with a controlled amount of water or other liquid upon entering mixer,

(C) a mixing element including a hollow shaft projecting into said drum, being eccentric to the axis of said drum and rotating at a more rapid rate than the drum, the mixing element rotating opposite to drum to achieve complete mixing,

(D) angular blades on said mixer are set to force material toward the outlet in the first two-thirds of its movement at the two-third point with angular paddles in opposite direction established to hold back the fiow and raise hydraulic level for extra mixing once it passes the row of opposite paddles with all paddles tending to force rapid discharge,

(E) and a spray located at the entrance of the drum to provide immediate wetting of dry aggregate followed by mixing by angualr blades on mixer and drum set to cause material to move to center section of mixer Where the asphalt emulsion or other mixing element is introduced from hollow shaft to complete mix with all components is given complete mixing by being held back by the opposite set of paddles on mixer until higher level causes fiow into final section for rapid discharge.

6. A mixing apparatus as set forth in claim 5 designed for milder blending by rotating both shaft and drum in the same direction, depending upon the cascading of material from drum combined with mixer to provide complete blending of less stable materials, where blades in the first two sections of drum and mixer have very slight angle, causing material to move to exit mostly by static head with blades in final section set to effect rapid discharge.

References Cited UNITED STATES PATENTS 509,560 11/1893 Carry 165-11 832,722 10/1906 Cunningham et a1. 259-l68 1,729,361 9/1929 Royer 259- 1,861,416 5/1932 Jaeger 259-169 1,960,704 5/1934 Hill 259-85 2,651,581 9/1953 Courtney 259-85 X 3,128,997 4/1964 Young 259-161 1,105,812 8/1914 McKaig 259-3 2,536,054 1/1951 Harrington 259-84 X 2,726,068 12/1955 Howden 259-3 2,989,291 6/1961 Bedner 259-85 X ROBERT W. JENKINS, Primary Examiner. 

1. A MIXING APPARATUS COMPRISING IN COMBINATION: (A) A FRAME, (B) A DRUM JOURNALED TO ROTATE ON SAID FRAME, (C) A PLURALITY OF RADIALLY INWARDLY PITCHED PADDLES FIXED TO THE INSIDE OF SAID DRUM, (D) A MIXING ELEMENT INCLUDING A SHAFT PROJECTING INTO SAID DRUM WITH ITS AXIS ECCENTRIC TO THE AXIS OF SAID DRUM, (E) A PLURALITY OF RADIALLY OUTWARDLY PITCHED PADDLES FIXED ON SAID SHAFT AND REVOLVED BY SAID SHAFT BETWEEN SAID PADDLES INSIDE OF SAID DRUM, (F) POWER MEANS ON SAID FRAME FOR SIMULTANEOUSLY ROTATING SAID DRUM AND SAID SHAFT, (G) A LONGITUDINAL PASSAGEWAY WITHIN SAID SHAFT, (H) RADALLY DISPOSED OUTLETS INTERMEDIATE ITS ENDS, (I) AND A SOURCE OF OIL CONNECTED TO SAID PASSAGEWAY OF SAID SHAFT FOR DISTRIBUTING OIL TO MATERIAL BEING MIXED IN SAID DRUM. 